Jib sheet shackle



Patented Sept. 21, 1948 s'rA'rE-s ATENT oFFlcE This invention relates to jlb sheet shackles, and particularly to quick-detachable and non-fouling shackles. Y

The httings now in use as jlb sheet shackles, and commonly known as boat snaps, comprise a hook with a spring-pressed tongue or keeper, and an eye or ring at the shank end ofthe hook. The jlb sheet ls either knotted through the eye or passed through and laced together with marline to form an eye in the sheet. These devices `are open to the two major disadvantages that the knot or laced eye tends to catch on any wire shroud or stay lt may encounter as the jlb ls .pulled from side to side; and the tongue of the snap hook will frequently be knocked open 'against a wire shroud or stay so that the jlb is fouled to the shroud or stay. It ls common practice in sailboat racing to lock the tongue to the snap hook with adhesive tape to prevent this fouling, but this is at best an awkward expedient v `and an annoyance because the jlb is taken ashore at the end of the race but the jlb sheet is left on the boat.

thas been proposed to make jlb sheet shackles with a bolt which ls passed through a crinale at the clew or bottom rear corner of the jlb, and is secured to a fitting on the jlb sheet by a nut, but such arrangements are open to the serious objection that the bolt or nut ls frequently dropped and lost overboard. 1

`rin object of the present invention is to provide a simple quick-detachable and non-'fouling jlb sheet shackle. An object is to provide a jlb sheet shackle in which the jlb sheet may be securely,

anchored without weakening the sheet, and which will not wear or abrade the sheet when in use. .An object is to provide a jib sheet shackle includlng a bolt to be passed through the crinale at the jlb sheet, the bolt and the associated parts secured' to the jibsheet being so constructed thatthe ybolt will not drop out when backed off for the introduction or removal of the jlb sheet' cringle. More specifically, an object is to provide a jlb sheet shackle comprising two mating plates of a generally U-ilorm, and a bolt threaded into both legs of the U'shaped assembly olmating plates; the plates having complementary recesses at their bases forming an arcuate passage for receiving the jlb sheet.

These and other objects and the advantages of the invention will be apparent from the following speciilcation when taken with the accompanying drawings in which:

Figs. 1 and 2 are perspective views, as seen from d` Claims. (Cl. 24-115) 2 y opposite sides of a jlb sheet shackle embodying the invention;

Fig. 3 is a front elevation of the shackle in Yplace on a jlb sheet;

Fig. t is a. section as taken on the planes indicated by line t-t of Fig. 3; and

Figs. 5 and 6 are perspective views of the coinplementary plates oi the shackle as seen from.

their inner faces.

In the drawings, the reference numerals l and i identify complementary plates oi approximately iJ-iorni which are secured to each other, in full surface contact, by screws t which pass through openings t in platei and are threaded into opening d of plate 2L Berni-circular grooves b, t' and l, ll are formed ln the ends of the legs of the lJ-shaped platesr i and 2, respectively. and these grooves mate and are allned transversely of the axis of the assembled plates to form-cylindrical openings which are threaded to receive a bolt having `an unthreaded central portion t of less 4diameter than a threaded portion t at its outer end for engagement in the threaded boreiormed by grooves t', l' of plates i and t, and an inner threaded portion lil for engagement` in the threaded bore formed by grooves 6, 'l of the plates. A spring lock washer li is arranged on the bolt at the base oi the threaded portion lil to seat between the inner radial surface of the milled head it of the bolt and a hat surface normal to the bolt axis and formed by mating flat l surfaces it; it of plates i, i. respectively.

The base portions oi the U-shaped plates l and t are relatively thick, as measured along the axis of symmetry of the assembled plates, and are pro vided with complementary grooves l5, IB which mate to form an arcuate 'passage of circular crosssection for receiving a jlb sheet S. A pin Il is swaged into one of the plates, for example plate 2, and projects into the lib sheet passage to penetrate the jlb sheet and anchor the shackle to the jlb sheet. The axisof the jlb sheet passage is circular or approximately circular, and thereby develops a snubbing action which materially reduces the strain on the anchor pin I1. The arcuate form of the jlb sheet passage has the further advantage that the jlb sheet S emerges from the shackle without bending, l. e. substantially in line with the pull on the jlb sheet, and thereby eliminates wear and abradlng of the jlb sheet.

As shown in Figs. 1 and `2, the bolt ls backed oi! to permit insertion or removal of the crlngle of the jlb from the jaw between the legs of the assembled plates I; 2 of the shackle, and lt is partlculailly t0 be noted that the bolt is securely held to the plates l, 2 by the threaded engagement Vof the outer portion 9 o! the bolt with the threaded bore formed by grooves 8, 'l of plates i. 2 respectively. It is possible, of course,- to remove the bolt completely from the assembled plates I, 2, and thereby give rise to a possibility of loss of the bolt but, except' by a deliberate backing ci! of the bolt far beyond the position which permits the attachment or removal oi' the shackle from the jib sheet cringle, there will be no danger of a loss of the bolt. Y

, 'I'he new shackle is non-fouling as it eliminates both the snap hook and the knotted or laced eye of the prior jlb sheet shackles, and it is readily coupled to or removed from the jib sheet upon manual adjustment of the threaded bolt. VSome of the previously proposed bolt type of shackles have been unsatisfactory as the bolt was'inadvertentlybacked oil by vibration due to slatting" of the jib sheet. This can not occur with the shackle of this invention as the spring washer.

il anchors the bolt against inadvertent displacement.

The drawing illustrates the presently preferred constructional form of the invention but it is to be understood that the invention is not limited to the construction `herein shown and described since various modifications which may occur to others tall within the spirit and scope of the invention as recited in the following claims. .I claim:

l. A jib sheet shackle comprising two complementary plates of approximately U-fcrm, the

25* in said complementary grooves, said plates having.

d bases o! the U-form plates being relatively deep as measured along the axis of symmetry or the plates, said bases having complementary grooves therein to receive a jib sheet, screw means for detachably securing said plates to each other,

alined complementary grooves in the legs of said U-iorm plates. said alined grooves being threaded, and a bolt having axially spaced threaded portions ior engagement in said threaded grooves of the plates, the bol't between said threaded portions being free from threads.

2. A jlb sheet shackle as recited in claim 1, wherein the axes of the grooves of the bases of said plates are approximately semi-circular,

3.'A jib sheet shackle as recited in claim 1, in combination with a pin secured to one of said plates and extending into said complementary grooves to penetrate and anchor therein a jlb sheet seated in said complementary grooves of semi-circular cross-section.

4. A jlb sheet shackle comprising complementary plates having complementary grooves therein to receive a jib sheet, means for detachably securing said plates to each other to anchor a jlb sheet projecting legs spaced apart to receive the cringle of a jlb, a bolt threaded into the ends of both of said projecting legs to extend through the'cx'ingle and a lock washer on said bolt to preclude in- 3o, advertent loosening of the same.

FREDERICK H. BRAKE. 

